Thermostat Controls, Sensors & Zoning Products
Thermostats and Accessories
HVAC Thermostats include low voltage (24V) and line voltage models, programmable and non-programmable, for single-stage, multi-stage, and heat pump systems. Control Sensor & Thermostat Accessories covers wall plates, guards, remote sensor kits, and C-wire adapters.
Sensors and Controllers
Sensors measure space, duct, outdoor, and water temperature, plus humidity, and report to a thermostat or controller. Controllers read those inputs and switch stages, fans, and dampers in HVAC automation controls.
Zoning Equipment
Zone Control Panels read each zone thermostat and call the equipment. Zone Controls, including dampers, actuators, and bypass controls, are the field side of HVAC zoning controls that direct airflow on command.
Ignition, Safety, and Limit Controls
Ignition Controls light and monitor burners on gas furnaces, boilers, and water heaters. Safety & Limit Controls, such as high limit and flame rollout switches, open the circuit when temperature exceeds a safe range.
Pressure and Temperature Controls
Pressure Controls monitor refrigerant, air, or water pressure and protect compressors, draft inducers, and pumps. Temperature Controls switch equipment on and off at a set point on boilers, unit heaters, and cooling equipment.
Refrigeration, Timer, and Lockout Controls
Refrigeration Controls include defrost timers and temperature controllers for walk-ins, freezers, and reach-ins. Timers & Lockout Controls hold a compressor or burner off after shutdown to prevent short cycling.
How It Works / Where to Use
The Control Sequence
A sensor measures a condition. A thermostat or controller compares it to a set point and calls the equipment. Safety and pressure controls stay in the circuit and stop the cycle when readings move outside limits.
Residential Heating and Cooling
On a gas furnace, the ignition control proves flame, while the high limit, rollout, and inducer pressure switches shut the gas valve if a limit opens. Zoning addresses floors that run warmer than others.
Commercial Buildings
HVAC monitoring and control relies on space, duct, outdoor air, humidity, and CO2 sensors. Controllers use those readings to stage equipment, open economizers for free cooling, and reduce runtime on unoccupied schedules.
Commercial Refrigeration
Pressure controls protect the compressor from low suction and high head pressure. Temperature and defrost controls hold box temperature. In a walk-in that runs warm, check controller readings and defrost settings first.
Key Specifications & Planning Steps
Voltage and Power
Low-voltage HVAC thermostats run on 24V from the equipment transformer. Line voltage models switch 120V or 240V directly for baseboard and resistance heat. Many connected thermostats also need a common (C) wire.
System Type and Staging
Confirm single-stage, multi-stage, heat pump with auxiliary heat, or dual fuel before selecting HVAC controls.
Range and Mounting
Match the set point range, differential, and switching action. Confirm sensor style: immersion, strap-on, duct, space, or outdoor.
Zoning Layout
Count zones, size dampers to the duct, and plan for static pressure.
Choosing the Right HVAC Control Equipment
For a replacement, match the voltage, switching action, range, and mounting of the original HVAC control equipment. For an upgrade, confirm the new control supports the system's stages and fuel. When adding a heat pump zone, choose a panel rated for heat pump operation, a thermostat per zone, and a bypass or variable speed strategy. For building-wide HVAC control solutions, plan sensor locations before choosing a controller. Compare heating and cooling controls by function first, then specification.
Frequently Asked Questions
What is the difference between a zone control panel and a zone control?
A zone control panel is the central board. It reads each zone thermostat and decides which dampers open and when the equipment runs. Zone controls are the field devices, such as motorized dampers and actuators, that carry out those commands in the ductwork. A zoned system needs both.
Do I need a line voltage or low voltage thermostat for baseboard heat vs a 24V furnace?
A low-voltage thermostat runs on 24V from the equipment's control transformer and is used with gas furnaces, air handlers, and heat pumps. A line voltage thermostat switches 120V or 240V directly and is built for electric baseboard and similar resistance heat. The two are not interchangeable, so check the heater's voltage and amp rating first.
My furnace igniter glows, the burners light, then it shuts off. What could cause that?
This pattern often means flame is not being proven after ignition. Possible causes include a dirty or misaligned flame sensor, a weak flame signal, a poor ground, reversed polarity, low gas pressure, or an ignition control that is not reading the signal. A limit or pressure switch opening can also end the cycle. Check flame signal, polarity, ground, gas pressure, and fault codes before replacing any control.
Can HVAC zoning controls fix an upstairs that runs hotter than downstairs?
In many cases, yes. HVAC zoning controls divide the ductwork into zones, each with its own thermostat, and use motorized dampers to send more conditioned air where it is needed. On an existing system, confirm the equipment and ductwork can handle zoning, including a plan to manage static pressure when fewer zones are calling.
How do I check if a thermostat or sensor is reading accurately?
Place a calibrated thermometer at the same height as the thermostat and compare readings after 15 minutes or more. Check that the thermostat or remote sensor is away from supply registers, exterior walls, windows, lamps, and direct sunlight. Review the temperature offset setting. A room can also feel colder than the air temperature because of drafts, cold surfaces, or low humidity.
Will a new thermostat work with an older system that has no C wire?
Many connected and Wi-Fi thermostats need a common (C) wire for continuous 24V power. Options include using a spare conductor in the existing cable, running new thermostat wire, or installing a C-wire adapter kit at the equipment. Some models run on batteries or power stealing, but compatibility depends on the thermostat and the system.
